He graduated from Stevens Point Area Senior High School in 1993 and went on to earn his bachelor's degree in political science from the University of Wisconsin–Madison.

Lassa's elevation created a vacancy in Wisconsin's 71st Assembly district, and Molepske chose to enter the race for the open seat.

He faced only one opponent in the race, the senior assistant district attorney, Veronica Isherwood, in the Democratic primary.

In the Fall of 2021, incumbent Wisconsin circuit court judge Robert J. Shannon filed his paperwork to indicate he would not run for re-election in 2022.

Molepske entered the race for the judicial post; he defeated attorney Stephen W. Sawyer in the Spring general election and was sworn in in August 2022.